Safety device.



G. JOHN. S AFETY DEVICE.

APPLICATION FILED APFLZT, I914.

Patented May 15, 1917.

I A TTORIVEY WITNESSES.

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GRIFFITH JOHN, OF YONKERS, NEW' YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

SAFETY DEVICE.

Specification of Letters Patent.

Patented May 15, 1917.

Application filed April 2'7, 1914. Serial N o. 834,668.

To all whom it may concern.

Be it known that I, GRIFFITH JOHN, a subject of the King of Great Britain, residing in Yonkers, in the county of Westchester and State of New York, have invented a new and useful Improvement in Safety Devices, of which the following is a specification.

My invention relates to improvements in safety appliances for elevators, and consists of a primarily operative quick acting arrester movable with the elevator car and adapted to engage suitable guide rails, and the combination therewith of a cushioning device of improved construction, which,

upon the engagement of the arrester with the guide rails, brings the moving parts to a gradual stop without shock or jar.

The invention also comprises means for resetting or returning the safety appliance to its initial or normal position upon the releasing of the primary operating device.

The device further consists of a safety appliance which is positive in operation, compact in arrangement of parts, and simple and cheap to manufacture.

Other objects of the invention will appear more fully hereinafter, the novel combinations of elements being pointed out in the appended claims.

In the accompanying drawings, Figure 1 shows an elevator car with the application of my invention thereto; Fig. 2 shows a section of an elevator car with the application thereto of a safety device constructed in accordance with my invention; Fig. 3 is a view similar to Fig. 2, but showing a modified construction; Fig. 4- is a side view of Fig. 2, showing the guide rail partly in section.

The elevator car travels over suitable guide railsBwhich are of the usual type. Essentially the safety appliance comprises a pair of buffer devices located underneath the car, each buffer device having a roll safety associatedtherewith which co-acts with the guide rails B.

Each buffer device comprisesa cylinder 1 which is suspended underneath the car by a rod 2, the said cylinder being seated against nuts 8, by a coil spring 4 carried by the rod. The cylinder is provided with asleeve 5 having graduated openings 6. A piston or plunger 7 is suitably fixed to channel beams 8, and fits into the sleeve 5. The piston is provided with an interior chamber 9, which communicates with the interior chamber 10 in the cylinder by means of a circumferential groove 11 on the outer periphery of the piston 7, and openings 12. A. sleeve 30 is formed integrally with the casing to accommodate the rod 2 and spring 4-, the sleeve being closed at the top to prevent passage of fluid therethrough from the chamber 10 to the chamher 9. The piston and cylinder are in normal position as shown, and attend; 13 sup plies liquid such as water or oil to the chambers 9 and 10. the said tank also serving as a discharge, as hereinafter described. The roll safety device comprises a block 141- (see Fig. 4:) made preferably of cast steel and formed integral with the cylinder 1. The block is provided with a slot 15, the metal on one side of the slot being cut at an angle and forming at the bottom of the block a pocket 16, which accommodates a roll 17 made of hardened steel and having a knurled cylindrical surface. The roll is maintained in position in the pocket and clear of the rail by means of a pin 18. A pair of lift rods 19, are connected to a system of levers 20 of the usual type on the top of the car, the rods having a lip 21 which extends underneath the roll, the lip being made narrow enough to permit the passing of the same between the pin and the slot. The rods are provided with a slot and pin connection 22, which serve to hold the lift rod in place and also guides the same when lifted, so that the lip undernea-th the roll followsparallel to the angle of the slot. A governor J of the ordinary type is mounted on the overhead beams 23. Around the sheave 24 of the governor passes an endless rope 25 which is held taut by means of a weighted sheave 26 at the bottom of the well. The governor cable is connected to the car at 27 to thelever system 20.

The operation of my improved safety appliance may beunderstood from the following explanation: Normally the governor rope travels with the car and rotates the sheaves at the top and bottom of the well,

governor operates the gripping device 28 to hold the rope stationary. The car continues to move, thereby causing the rope to actuate the lift rods 19. This raises the roll 17, causing its knurled surface to engage with the angular side of the slot on one side and the side of the rail on the other, when it rolls along and until it is jammed between the two. The powerful wedging eflect thus produced brings the casing to a comparatively quick stop, and the continued descending movement of the car is resisted by the fluid contained in the chambers 9 and 10, which fluid is now forced by the piston into the tank 13. As the area of the openings 6 is very large at the top, very little resistance is offered to the flow of fluid during the initial movement of the piston, and the latter is thus enabled to accelerate very rapidly, the pas-- sage of fluid from underneath the piston being byway of the openings 6, into the groove 11in the piston, through the opening 12, into the chamber 9, and so on into the tank 13. The circulation of fluid as above noted continues as the piston descends, the restriction producing a constant retarding force as the size of theopenings 6 diminish, thusthe car is gradually retarded and brought to a final stop when the piston reaches the bottom of the openings 6. Thespring 1 serves as a positive return for the cylinder 1 to its normal position upon the disengagement of the roll from the rails. The movement of the cylinder to its normal position creates a suction, and consequent sucking of the fluid from the supply tank 13 into the chambers 9 and 10. 7

While in the appliance shown in Fig. 2 I provide a sleeve having' graduated openings, whereby the retarding effect is constant, I also provide a modified construction as shown in Fig. 3, wherein the'graduated sleeve is omitted, and which approximates a constant retarding eifect, this arrangement permitting of a much simpler construction than that shown in Fig. 2. The appliance shown in Fig. 3 comprises a cylinder 1, which is suspended underneath the car by a rod 2, the cylinder being held against nuts 3 by a coil spring a; The piston or plunger 7 is suitably fixed to the channel beams 8, and fits into the cylinder 1. The piston is provided with an interior chamber 9 which communicates with the chamber 10 in the cylinder, by means of the opening 30. The two chambers are filled with oil from the supply tank 13. The roll safety is of substantially the same construction as the one heretofore described, and upon the operation thereof, the cylinder is brought to a comparatively quick stop, and the continued descending movement of the car, causes the piston to displace the fluid contained in t'hechambers 9 and 10, forcing cylinder from the car, means movable with ment of the piston into the cylinder.

the same through the opening 31, and so on into the tank 13, and it'will thusbe seen that the retarding effect of the fluid remains practically constant throughout the entire movement of the piston, the retarding force thereof being dependent on the size of the opening 31, which may be made of any size 7 desired, to give to the oil the retarding effect desired. Upon releasing the roll from its wedging position, the spring 4 returns the cylinder to its normal position, which movement thereof sucks the oil from the tank and into the chambers 9 and 10..

Various changes in the detail and arrangement of parts might be made by those skilled in the art without departing from the spirit and scope of my invention, I desire therefore not to be limited to the particular construction disclosed.

What I claim is 1. In a safety appliance for elevators, the car, guide rails therefor, means for engaging the guide rails when the car attains an undue speed, andcushioning means for gradually arresting the car, when the said means engage the guide rails, the cushioning means comprising a cylinder having graduated openings and rigidly connected with the first named means, a piston having openings therein and fixed to the car and movable in the cylinder, the graduated openings in said cylinder cooperating with said openings in the piston, and means independent of the piston for supporting the cylinder on the car.

2. In a safety appliance for elevators, the car, a fluid cylinder carried by the car, a piston fixed to the car and movable in the cylinder, the said piston having an interior chamber communicating with the cylinder chamber, means for arresting the cylinder, and means independent of the cylinder and piston for receiving the discharge fluid upon the movement of the piston into the cylinder.

3. In a safety appliance for elevators, the car, a fluid cylinder, a piston fixed to the car and movable in the cylinder, the said piston having an interior chamber communicating with the cylinder chamber, means independent of the piston for suspending the the car for arresting the cylinder when the carrattains an undue speed, and means independent of the cylinder and piston for receiving the discharge fluid, upon the move- 7 4. In a safety appliance for elevators, the car, a fluid cylinder carried by the car, a piston fixed to the car and movable in the cylinder, the said piston being in plunger form and having a chamber communicating with the fluid in the cylinder, the cylinder havin graduated openings cooperating with t e piston chamber to effect a gradual retardation oi the piston in the cylinder, and means for arresting the cylinder when the car attains an undue speed.

5. In a safety appliance for elevators, the car, a fluid cylinder carried by the car and having a sleeve therein provided With graduated openings, a piston fixed to the car and movable in the said sleeve, the piston being in plunger form and having a chamber communicating with the interior of the sleeve, a tank carried by the car and communicating With the piston chamber, and means for arresting the cylinder When the car attains an undue speed.

6. In a safety appliance for elevators, the car, guide rails for the car, a pair of cylinders carried by the car, each cylinder having mechanism formed integrally therewith comprising a roll safety mechanism and pro vided With graduated openings, pistons fixed to the car and movable in the cylinders and provided with an interior chamber com municating with the cylinder chamber, the graduated openings of the cylinder chamber cooperating'ivith the interior chamber of the pistons to eflect a gradual application of the roll safety, a fluid tank carried by the car and communicating With the chambers in the pistons, means independent of the pistons for suspending the cylinders below the car, and yielding means for returning the cylinders to normal position relatively With the piston upon the releasing of the roll safety mechanism from the guide rail.

7. The combinationvvith an elevator car,

of a safety device therefor comprising a pair of cylinders suspended from the car, pistons fixed to the car and movable in the cylinders, the said piston having an interior chamber communicating with the cylinder chamber, a supply and discharge tank carried by the car and communicating With the piston cham her, and means associated With the cylinders for arresting the same When the car attains an undue speed.

8. The combination with an elevator car, of a safety device therefor comprising a pair of cylinders suspended from the car, each cylinder having a sleeve provided with graduated openings, pistons fixed to the car and movable in the sleeve, each piston having a circumferential groove, an interior chamber communicating with the cylinder chamber, by means of said circumferential groove in each piston, each piston having an opening communicating With the said groove from the piston chambers, means independent of the pistons for suspending the cylinders below the car, a supply and discharge tank carried by the car and communicating with the piston chambers, guide rails for the car, and means for arresting the cylinders When the car attains an undue speed.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

GRIFFITH JOHN.

Witnesses:

JOHN D. IHLDER, O. SOHAEFER.

fiopies of this patent may be obtained for five cents each, by addressing the commissioner of Patenta,

Washington, D. G. 

